A blower of the above-mentioned type is known in the form of a radial blower from document EP 2 236 838 A1. The electric motor hereby driving the blower wheel positioned inside the blower housing is constructed as an external rotor motor and is positioned inside the blower wheel. In addition, the electric motor is constructed as an electronically commutating direct current motor, frequently also called an EC motor, for which reason a control electronic unit is required for electronic control. In the known blower, this control electronic unit is housed in a unit known as a terminal box which is secured as the attachment housing outside on the blower housing. By using an EC motor this known blower has advantages which, however, have shown in practice that the operating characteristics are still not optimal.
A similar blower is described in EP 0 985 829 B1, wherein an attachment housing secured externally on the blower housing is disclosed solely as a terminal box—which aside from electrical connections for connecting between the connection lines of the electric motor and an external connection cable also contains an operational capacitor required for alternating current motors.
Finally, the publication EP 1 484 509 B1 describes a double blower arrangement with two radial blowers powered by a common coaxial electric motor, wherein the electric motor is located outside between the two blower housings and supports the two radial blower wheel across axially opposed shafts. Here, too, a terminal box is secured externally on one of the two blower housings.